Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
These are similar to memdup() and newdup(), but reserve one extra NUL
byte at the end of the new allocation and initialize it. It's useful
when copying out data from fixed size character arrays where NUL
termination can't be assumed.
